📈 Analytics & Metrics

Customer Acquisition Cost

cac · customer acquisition cost · cost of acquiring a customer · acquisition cost · cost per acquisition customer · ltv to cac

Definition

CAC = marketing and sales spend / number of new customers in a period. It matters to calculate CAC per channel: CAC from paid search, SEO and email differ radically, and a blended CAC hides the inefficiency of individual sources.

Formula and calculation

CAC = Marketing and sales spend / Number of new customers

Example: a marketing budget of $5,000 a month and 250 new customers gives CAC = $20.

CAC by channel

Blended CAC is an average that hides the real picture. Always calculate CAC per channel:

Channel	Typical CAC	Note
SEO / organic	Low	Long-term, requires investment in content
Email marketing	Very low	For reactivating an existing base
Paid search	Medium to high	Scales, but gets more expensive
Paid social	Medium	Depends on the audience and bids
Referral programme	Low	Customer brings customer

LTV to CAC: the key ratio

Ratio	Interpretation
< 1:1	Critical — every customer loses money
1:1 – 2:1	Dangerous — no margin left to grow on
3:1	The e-commerce norm
5:1+	Good, but you may be underinvesting in growth

How personalization improves unit economics

Personalization affects the CAC metric indirectly, through two mechanisms:

Higher site CR → fewer clicks are needed per conversion → the cost of a conversion from paid traffic falls
Higher LTV → at the same CAC, every acquired customer brings more revenue over their lifetime → the LTV:CAC ratio improves

Neither mechanism touches the media buying itself, which is why CAC should be tracked alongside LTV rather than on its own: a campaign that pushes CAC down by targeting only the cheapest audiences usually pulls LTV down with it, and the ratio ends up worse than before.

Frequently asked questions

How do you calculate CAC?

CAC = all marketing and sales spend for a period / number of new customers in the same period. Example: you spent $5,000 and acquired 250 new customers, so CAC = $20. Note: count new customers, not all orders.

What LTV to CAC ratio is considered normal?

The e-commerce standard is LTV:CAC ≥ 3:1. That means if CAC is $20, LTV should be $60 or more. A ratio below 2:1 means the business spends almost as much on acquisition as it earns. Above 5:1 you may be underinvesting in growth.

How does personalization affect CAC?

Personalization does not lower CAC directly — it raises LTV. But with a fixed acquisition budget, higher LTV improves the LTV:CAC ratio and makes every unit of acquisition spend more profitable. On top of that, personalization raises site CR, which lowers the cost of a conversion from paid traffic.